[External] Re: IPv6 uptake

Mon Feb 19 16:17:10 UTC 2024

On Mon, Feb 19, 2024 at 11:13 AM Hunter Fuller via NANOG
<nanog at nanog.org> wrote:
>
> On Mon, Feb 19, 2024 at 9:29 AM Mike Hammett <nanog at ics-il.net> wrote:
> > "In IPv6's default operation, if Joe has two connections then each of
> > his computers has two IPv6 addresses and two default routes. If one
> > connection goes down, one of the routes and sets of IP addresses goes
> > away."
> >
> > This sounds like a disaster.
>
> You know, I thought so too, until I deployed it and it worked fine.

Years ago we made "source specific routing" the default in openwrt.
This means all hosts get both sets of prefixes, and naturally retry
other src addresses.

To what extent anyone else has adopted this is unknown. The popular
mwan3 code is kind of hairy vs a vs ipv6 here.

> I have done it twice now, once on MikroTik RouterOS and once on
> Ubiquiti EdgeOS. You just have to make sure the timers are pretty
> short, and that the router will stop sending RAs for the route if it's
> not working. This is definitely something that a COTS SOHO dual WAN
> router, that Joe would buy, could and should do by default (hopefully
> they do; I just haven't checked).
>
> --
> Hunter Fuller (they)
> Router Jockey
> VBH M-1C
> +1 256 824 5331
>
> Office of Information Technology
> The University of Alabama in Huntsville
> Network Engineering

-- 
40 years of net history, a couple songs:
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Dave Täht CSO, LibreQos